Definition: In this task, you are given an input list A comprising of numbers and alphabets. You need to extract and sort the unique alphabets in the list. The alphabets in the input list will only be in lowercase. Return -1 if there is no alphabet in the input list.
Input: ['o', 'j', '4229', '4955', 'i', 'b', '25', '783', 'q']

b, i, j, o, q